Grid winding machine



y 1965 D. s. NOILES ETAL 3, 9 07 GRID WINDING MACHINE Filed May 23, 1962 mveur'ofis Donald A. Boylon WITNESSES 8| Douglas G. Noiles.

ATTORNEY 2 United States Patent This invention relates to apparatus and methods for manufacturing electrodes (comprising support rods and grid turns wound on these support rods) for use in electron tubes and, more particularly, to the manufacture of grids in which at least a part of the turns are of non uniform spacing. This invention has particular application, although it is not limited to the manufacture of so-called frame grids where the turns of the grid wires, at least for some time during the grid manufacturing process, are held in their spaced relationship by their own nsion and concurrent friction at their points of contact with the frid frame. It is often desirable in the manufacture of grids for electron discharge devices that a certain portion, or portions, of the grid have turns which are of a d rerent displacement or )acing from that of the ing turns of the grid. This non-uniformity is for the purpose of acheving some particular characteristic, for example, a remote cutoff characteristic.

In a conventional grid lathe, the grid turns are wound about the frame and nonuniformity in grid turn spacing is obtained as the diiferential sum of the uniform advance or spacing rate of a lead screw (or a first cam) and the non-uniform spacing rate of a second cam. And, conventionally, the lead screw (or first cam) and the second cam are in continuous motion during the cycle for winding one complete grid. This technique imposes two conditions on the combination of the machine and the grid. First, adding the cyclically varying motion of the constantly rotating second cam to the uniform motion of the lead screw (or first cam) to produce a cyclical uniform and then non-uniform motion of high accuracy requires extremely precise and expensive machine parts and cams. Grid turn spacing accuracies of the order of .0001 inch are desired. Second, this arrangement requires that different grid winding specification each be provided with a specially designed and fabricated set of cams-a requirement that serves admirably to point out the great expense involved in ohtair'ng the number of precision cams necessary for the variety or" different grid designs.

It is, therefore, an object of this invention to pro vide an improved grid winding mechanism.

A further object is to provide a grid winding mechanism having improved means for winding variable pitch grids.

Another object of this invention is to provide an improved method of winding variable pitch grids.

A stil further object is to provide means which are readily adaptable to standard grid lathes for winding variable pitch grids.

Still anot" er object is to provide an improved means for Winding variable pitch grids which is readily adjustable to the winding of different variable pitch grid structures witr ut the need for special cams for each different grid specification. rid winding can be accomplished by many combinations of motions. (1) The frame can rotate and be ion" y in ved to draw wire from a spool whose axis is fixed, or the spool of wire can be made to rotate and move longitudinally around a non-rotating frame. (2) The frame may be longitudinally moved relative to a rotating wire guide, or conversely, the wire guide may traverse the length of a rotating grid.

Stated briefly, the present invention in its preferred form provides for the winding of a grid structure having a portion of its turns of difierent spacing by providing that a draw bar which supports and rotates the grid support rods and a guide member which directs the grid wire onto the rotating support rods move relative to one another to provide the difference in spacing between grid turns. The draw bar is then uniformly advanced by suitable means such as a lead screw construction while non-uniform movement of the guide member is efiected through the use of a specially constructed cam member which is intermittently operated at predetermined periods to provide movement of the guide member. The specially constructed cam member is provided with a plurality of adjustable cam surfaces, which through proper mechan ical linkage, determine the amount of movement of the grid wire guide member.

Further objects and advantages of the invention will become apparent as the following description proceeds and features of novelty which characterize the invention will be pointed out in particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which:

FIGURE 1 is a perspective view of a portion of a standard grid lathe machine which has been adapted for the winding of grids having an area of non-uniform grid turn displacement in accordance with the present invention;

FIG. 2 is a front view of one of the cam members utilized in the embodiment of FIG. 1 which is useful in the explanation of the present invention; and

FIG. 3 is a segment of a grid strip which is wound in accordance with the present invention and which has areas of nonuniform turn displacement.

With reference now to P16. 1, there is shown a variable pitch mechanism such as would be applied and utilized on a standard grid lathe such as the RCA Model 705Y which is widely used in the industry. As is the case with these lathes, there is shown a draw bar lit which is caused to rotate at a prescribed rate by means within a housing 12. The free end of the draw bar Zlil is provided with a suitable holding means such as a vice clamp 14 which includes a pair of jaws l6 and i8 and a locking handle 26. As well as rotary movement, the draw bar it) is given movement along its longitudinal axis by means of a rotating lead screw 26. The lead screw 26, which is maintained stationary along its longitudinal axis, acts through a connecting member 28, which is fixed to the draw bar ill by means of a pair of collars 29 to provide a uniform longitudinal movement of the draw bar ill. Suitable means for providing the draw bar ill with a simultaneous rotating and longitudinal motion are well known in the art and found on many grid lathes such as the RCA model set forth above. The actual means by which this draw bar lid is provided with these movements is not of prime importance to the invention; the important feature being that the bar is given these simultaneous movements.

One end of a grid strip 22 having a pair of spaced support rods 23 and 24, onto which a grid wire is to be wound, is held by means of the clamp member 14. Cross members 25 maintain the rods 23 and 24 in a spaced relationship. The other end of the grid strip 22 is guided through the rotating hollow headstock spindle 0f the grid lathe by suitable means which are not shown. The grid strip 22 is provided with longitudinal motion and rotary motion about its longitudinal axis in accordance with the action of the draw bar lit.

In FIG. 3 there is shown a section of a grid strip 22 which is wound with a variable pitch or non-uniformly spaced portion of grid turns. As shown in FIG. 3, the section of the strip 22 includes one complete grid and portions of two other grids. The grid strip 22 comprises a pair of parallel spaced side support rods 23 and 24 around which is wound a plurality of grid turns 30 of grid wire. The grid strip 22 includes a plurality of sections such as is shown in FIG. 3; the number of sections is largely dependent upon the physical capabilities of the machine upon which the strip is being wound. For the sake of explanation the grid has been designated in several portions defined by the characters 32 through 41. After the entire grid strip has been wound and the turns 30 aflixed to the side rods 23 and 24 by suitable means such as through the utilization of glass frit, those turns which are in the areas defined by 32 to 35 and 33 to 41 are removed. The strip is then severed at points 33 and 39 and this portion, lying between these two points, constitutes one complete grid. Those portions of the side rods between points 33 to 35 and 38 to 39 serve as the support legs for the grid, while the portion of the grid defined by points 35 to 38 define the active grid portion. With reference now to the active grid portion 35 to 38, it is seen that from point 35 to point 36 the grid turns are of uniform spacing. The same spacing is also found between points 37 and 38. However, between points 36 and 37, the spacing between successive grid turns has been increased so that in this area there are less turns per inch than in the remaining part of the active grid portion. It is also noted that the grid turns lying in the area from points 33 to 34 and 39 to 48 are more closely spaced than even those between the points 35 to 36, and 37 to 33. The reason for this latter change in the spacing of turns will be explained later. It is the variable pitch or more widely spaced portion of the grid turns between points 36 and 37 with which this invention is primarily concerned.

With reference once again to FIG. 1, there is shown in its preferred embodiment, the mechanism for winding the non-uniformly spaced grid turns as are shown in FIG. 3 (between points 36 to 37). This mechanism comprises a cam 42 which includes a disc member 43 which in turn is provided with a plurality of stud members 44 located in a circular array on one flat face of the disc 43. The studs 44 are located near the edge of the disc 43 and protrude from the face thereof in a direction which is substantially perpendicular to the face of the disc 43. The studs 44 are preferably in the form of screws having threads which correspond to internally threaded holes within the disc 43. Preferably, the studs 44 are provided with fiat faces 45 and are of sufficient length to extend through the disc 43. Thus, the height of the studs 44 with respect to the face of the disc 43 may be adjusted from the back side of the disc 43 by turning the studs through suitable means, for example a screw slot.

A cam follower 46 has a flat face 47 which is wide enough to span from one screw to the next. The earn follower 46 is also provided with a beveled edge 48 extending to the flat face 47 which enables the follower 46 to slide up on a stud 44- which is higher than the one upon which it is presently resting. The follower 46 is connected to the free end of a lever 50 which has its other end pivotally attached at 53 to a post 52 which is stationarily mounted. Spring means 54 are provided, acting between a fixed support not shown and the lever 50, to maintain the cam follower 46 in firm contact with the face 45 of the studs 44.

A grid wire 31, which is supplied from a suitable source such as a spool of wire (not shown), is directed onto the rotating grid strip 22 by means of a suitable guide member 70. The guide 70 may take on any suitable form and is shown to comprise a rigid flat member 72 and a resilient leaf 71 which is bent at the top to allow easy insertion of the wire into the confined space between the members 71 and 72. The guide member 76 is connected to a block 68 which in turn is connected to a support block 66. The block 66 is shown to be of dovetail construction and is designed to be slidably supported within a mating dovetail slot 64 which is located in a fixed support block 62. The construction as has been described above maintains the guide member 70 in a fixed relationship with respect to height and distance away from the rotating grid strip 22 but permits relative motion of the guide 70 with respect to the grid strip 22 in a direction which is parallel to that of the axial movement of the strip 22 occasioned by the draw bar 19 acting through the lead screw 26. It is, of course, recognized that other constructions may be utilized to achieve the above results as to relative movements.

A tie rod 58 connects the block 66 with the lever One end of the tie rod 58 is pivotally connected to the block 66 while the other end of the tie rod 58 is pivotally connected to the lever St) at a convenient distance between the pivot point 53 and the cam follower 46. In the drawing, the pivot point of the tie rod 53 to the lever 56 is designated as 56. While this is not a critical feature, in the preferred embodiment the ratio of he distance from the cam follower 46 to pivot point 56 and pivot point 56 to pivot point 53 is ten to one. The height of the studs 44- may be adjusted, by reference to conventional displacement gages, to an accuracy of $0002 inch and with the above set forth ratio of pivot distances, the resulting displacement of the guide member 79 is ten times as accurate or :00002 inch.

The cam 42 is rotated by a ratchet disc 69 which preferably has the same number of teeth as there are studs 44 on the cam 42. The ratchet 69 is attached to a shaft 73 which in turn is affixed to the cam 4-2. Cam 52 and its shaft 73 are journaled and spring loaded against a precisely lapped thrust bearing. Thus, the cam itself is axially stable to better than .0001 inch. The ratchet 69 is driven by a pair of pawl arms 74 and 76 which operate in a reciprocating mode, in stepped fashion, to provide that only one of the pawls is in engagement with the ratchet at any one time. This step-like reciprocating motion is achieved through the use of two eccentrics 73 and 80 which are, respectively, in an operating relationship with the pawl arms 74 and 76 and which are secured to a shaft 81. Shaft 81 rotates at the same speed as the speed of rotation of the draw bar 10. Thus, one revolution of the draw bar 10, which corresponds to one complete grid turn, will correspond to one complete revolution of the shaft 81. Each complete revolution of shaft 81 results in a single actuation of each of the pawls 74 and 76 to move the ratchet 69 radially two teeth. This corresponds to an indexing of the disc 4-2 a sufficicnt amount to bring two stud members 44 successively under the cam follower 46. Stated more simply in terms of end result, when one pawl arm 74 or 76 is in engagement with the ratchet 69, one half turn of shaft 81 which corresponds to one half grid turn, causes one stud member to be advanced under the cam follower 46. Also, while one half grid turn is being made, the lead screw 26 will advance the draw bar 10 and hence the grid strip 22 a longitudinal amount equal to one half the normal spacing between two successive grid turns 30.

While the pawl arms 74 and 76 are continuous in their driving action, it is desired in the present invention that the cam 42 be rotated only during those periods where it is necessary or desirable to have a change in spacing between successive grid turns. To this end, suitable means are provided for bringing the pawl arms 74 and 76 into and out of engagement with the ratchet 69. The pawl arms 74 and 76 are brought into engagement with the ratchet 69 by suitable means, for example, a pair of tension springs 75 and 77 each having one end thereof attached, respectively, to the arms 74 and 76 and the other end thereof attached to a fixed reference which has not been shown. The pawl arms 74 and 76 are brought out of engagement with the ratchet 69 through the ultilization of a lever 82. Lever 82 is provided with a block 84 at its lower end below which the two pawls 74 and 76 extend. Lever 82 is pivotally connected through a bearing member 86 to a linkage 37 which in turn is connected to a cam follower 92. The cam follower 92 is responsive to a second cam 94 which is attached to a rotating shaft 96. Shaft 96 is driven by suitable means within a housing 110 to provide that cam 94 makes one complete revolution for each grid. The cam 94 acts as a stop-start control for the variable pitch mechanism and does not otherwise control the variable pitch grid turns themselves. The cam 94 itself may be made up of two discs 95 and 97 which are movable with respect to one another and which, as will be explained later, varies the number of variable pitch turns.

The lever 82 is also operably connected to an armature 98 which is in an operative relationship with an electrical solenoid lltltl. Thus, the pawl arms 74 and 76 may be brought into contact with the ratchet 69 not only through the operation of the cam 94 and the cam follower 92 but also through the energization and deenergization of the solenoid 199. That is, energization of the solenoid ltltl acting through the armature 98 and lever 32 disengages the pawls '74 and 76 from the ratchet 69. A subsequent deenergization of the solenoid 199 will permit the pawl arms 74 and 76 to be brought into active ongagement with the ratchet 69.

The operation of the mechanism heretofore described is basically as follows. The grid strip 22 is loaded into the machine and clamped to the draw bar it? by means of the clamp 14. The machine is now started and the draw bar begins to rotate and move to the left under the influence of the lead screw 26. At the beginning of a new grid member (corresponding to point 35 of the grid in FIG. 3), the block 66 is in its far left position, and the cam 32 is positioned so that the lowest stud Ml is under the cam follower 46. The cam 94 is now at a position represented by A in FIG. 2. Also at this time the solenoid lltlll is energized and hence acts through lever 82 to provide that pawls '74 and 76 are held out of engagement with ratchet 69 even though they are reciprocating under the influence of the eccentrics 78 and till. Therefore, ratchet 69 and cam 42 are stationary. Thus, at this time, the strip 22 is being moved to the left by the action of the lead screw 26; the spacings of the grid turns are the function solely of the lead screw 26; and the spacing is thus uniform as is shown in the area between points 35 and 36 of FIG. 3. As the grid strip 22 advances to the left the cam 94 continues to rotate so that at some predetermined place between points 35 and 36 of FIG. 3, the cam 94 occupies a position such that the raised portion 102 comes under the cam follower 92. At point B on the cam 94 the solenoid 199 is deenergized and the control of the lever 82 is given solely to the cam 94.

When the cam 94 reaches point C, which corresponds to point 36 on the grid in FIG. 3, the cam follower 92 is permitted to drop. Accordingly, lever 82 and member 84 rise and allow pawls 74 and 76 to engage the ratchet 69. The portion of the cam 94 between points C and D correspond to that portion of the grid between points 36 and 37 where it is desirable to have the variable pitch turns or turns of unequal spacing. With the pawls 74 and '76 now in engagement with the ratchet 69, the ratchet will turn and hence drive the cam 42 in a clockwise direction so that successively higher stud members 44 will be brought under the cam follower 46. With successively higher studs 44- being brought under the cam follower 46, the cam follower 46 is forced to the right and this movement is transmitted through the lever Bill and the tie rod 58 to force the block as to be moved to the right. Thus, the guide member 79 and hence the grid Wire 31 are moved to the right. It is understood that during the time that the guide member 70 is moving to the right, the draw bar it) continues its rotation and advancement to the left. Thus, it is readily seen that the combined action of these two members, results in a widening of the space between the successive turns 39 of the grid.

When the desired number of variably spaced grid turns have been wound (corresponding to point 37 of the grid in FIG. 3 and point D on the cam 94) the cam follower 92 is caused to rise due to the upraised portion 194 of the cam 94 which movement in turn acts through the lever arm and its member 8 tto disengage the pawls from the ratchet 69. At this point, the guide member 3% is once more stationary. With the guide member 79 stationary, the spacing of the turns is once again determined solely by the action of the lead screw 26 and the turns are more of the original spacing such as is found in the area between points 35 and 3-6. This evenly spaced turn area is defined by the points 37 and $3 in FIG. 3. While the turns in the area defined by 3'7 and 38 are being wound, the cam 94 continues to rotate and when the cam follower 92 reaches a point E on the portion N4 of cam 9- 3 the solenoid is once more energized. The control of the pawls is thus returned to the solenoid so that when point P on cam 94 is reached, the cam follower 92 will not be permitted to drop and engage the pawl arms with the ratchet 59.

Inasmuch as the guide '79 is at its far right position at this time and it is necassary that before the initiation of the winding of the next grid member that it be in the left-hand position, at some point between the winding of the two grids it is necessary to index the system back to its original point. Therefore, at an appropriate point on the cam 9 such as that represented by G which corresponds to point 39 in FIG. 3 (in the leg portion of the grid), the solenoid is deenergized allowing the pawls once again to be operative upon the ratchet 69 and once more the cam 4-2 is caused to rotate. The studs during this rotation are of decreasing height so that the cam follower and hence the guide member are moved to the left. The movement of the draw bar 10 and the guide member '79 are now in the same direction and the turns wound during this period will be of closer spacing than those produced under the action of the lead screw 26 alone. This is shown as the area between points 39 and 419 (also to When the cam has completed one revolution and is back to its original point, which corresponds to point 4% in FIG. 3 and point H on the disc 91, the solenoid is reenergized, thus disengagin the pawls 'id and ts from the ratchet 69 and the spacing of the grid wires is once again solely the unction of the screw Under the action of the cad screw 26 the remaining turns in the leg portions of the grid strip are wound. When the strip reaches a point 41 on a second grid member (corresponding to point of the grid just wound), the cam 94 is once again at point A with all of the rest of variable pitch mechanism once more at its starting point.

It is readily evident that the above-described system (using both a cam member and a solenoid to control the stop and start of the variable pitch mechanism) may be replaced solely by a cam member or by a solenoid control. However, with the of the twopiece cam 94 such as has been described, the number of variable pitch turns is readily varied merely by adjusting the two pieces 95 and 97 relative to one another so that the spacing between points represented by C and D is changed. Although the device would work equally well if completely cam controlled, it would lack some of the versatility of the present system. Likewise, if the system were controlled solely through the use of the solenoid 1-596 considerable effort would have to be expended in the exact timing of the energization and deenergization of the solenoid. in the present embodiment the only critical period of energization and deenergization of the solenoid M0 is the length of the time when the mechanism is reset to its original position, or the length of time represented by points G and H on the cam The embodiment thus described provides a cam structure which intermittently effects the movement of the wire guide which when combined with the constant rate of the grid strip motion results in grid turns of varied spacing. It is noted that through the utilization of the present invention, changes in grid design do not necessitate a redesign of the cams but merely a resetting of the adjustable components of the present mechanism.

While there has been shown and described what is at present considered to be the preferred embodiment of the invention, modifications thereto will readily occur to those skilled in the art. For example, as has been previously stated the engagement and disengagement of the pawls with the ratchet may be controlled by other means than the mechanical-electrical system described and in addition the exact mechanism for engaging and disengaging the pawls with the ratchet is not critical in that other forms of actuating devices other than that shown may be utilized. It is also obvious the same result could be achieved by using the intermittently driven adjustable cam disc to cause cyclical axial displacement of the lead screw, which cyclical axial displacement would add to, and subtract from the uniform axial displacement of the grid strip created by the rotation of the lead screw.

It is not desired, therefore, that the invention be limited to the specific arrangement shown and described, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

We claim as our invention:

1. A grid winding machine of the lathe type in which grid wire is wound about spaced support rods comprising means for rotating said support rods, means for advancing said support rods in the direction of their rotational axis at a uniform rate, guide means for directing said grid wire onto said rotating support rods, said guide means displaceable in a direction substantially parallel to the direction of advancement of said support rods, and means responsive to the motion of said support rods for moving said guide means.

2. A grid winding machine of the lathe type in which a grid wire is wound about a pair of spaced support rods comprising means for rotating said support rods, means for advancing said support rods in the direction of their rotational axis at a uniform rate, guide means for directing said grid wire onto said rotating support rods, said guide means movable in a direction substantially parallel to that of the direction of advancement of said support rods, and means associated with said means for advancing for moving said guide means during the advancement of said side rods to provide different spacings between selected turns of said grid wire on said side rods.

3. A grid winding machine of the lathe type in which a grid wire is wound around a plurality of spaced support rods comprising mean for rotating said support rods, means for advancing said support rods in the direction of their rotational axis, a guide member for directing said grid wire onto said support rods, said guide member displaceable in a direction substantially parallel with respect to the direction of advancement of said support rods, and means for effecting the movement of said guide member, said latter means comprising a rotatable cam and means operably connecting said cam and said guide member whereby rotation of said cam effects the movement of said guide member.

4. A grid winding machine of the type in which a grid wire is wound around a plurality of spaced support rods comprising means for rotating said support rods, means for advancing said support rods in the direction of their rotational axis simultaneously with said rotating movement, a guide member for directing said wire onto said support rods, and means for displacing said guide memher in a direction substantially parallel to the direction of advancement of said support rods, said latter means comprising a rotatable cam having a plurality of cam surfaces of varying heights, and means operably connecting said guide member and said cam whereby rotation of said cam effects movement of said guide member, said movement being responsive to the height of said cam surfaces.

I 5. A grid winding machine of the type in which a grid Wire is wound around a plurality of spaced support rods comprising means for rotating said support rods, means for longitudinally advancing said support rods simultaneously with said rotating movement, a guide member movable in a longitudinal direction with respect to the direction of advancement of said side rods for directing said grid wire onto said rotating support rods, means for effecting the movement of said guide member, said latter means comprising a rotatable cam having a plurality of cam surfaces of varying heights, the height of each cam surface being individually adjustable, and means operably connecting said guide member and said cam whereby rotation of said cam effects the movement of said guide member, said movement being responsive to the height of said cam surfaces.

6. A grid Winding machine of the type in which a grid wire is wound around a plurality of spaced support rods comprising means for rotating said support rods, means for longitudinally advancing said support rods simultaneously with said rotating movement, a guide member movable in a longitudinal direction with respect to the direction of advancement of said side rods for directing said grid wire onto said rotating support rods, means for effecting movement of said guide member, said latter means comprising a substantially flat disc having a plurality'of stud members positioned in a circular array on one face thereof, said stud members being individually adjustable in height with respect to the face of said disc, means for rotating said disc about its center, and means responsive to the height of said stud members and operably connected to said guide member whereby movement of said guide member is effected in accordance with the height of successive stud members.

'7. A grid winding machine of the type in which a grid wire is wound around a plurality of spaced support rods comprising means for rotating said support rods, means for longitudinally advancing said support rods simultaneously with said rotating movement, a guide member movable in a longitudinal direction with respect to the direction of advancement of said side rods for directing said grid wire onto said rotating support rods, means for effecting the movement of said guide member, said latter mean comprising a substantially flat disc having a plurality of stud members positioned in a circular array on one face thereof, said stud members being individually adjustable in height with respect to the face of said disc, means for rotating said disc about its center, and means responsive to the height of said stud members and operably connected to said guide member whereby movement of said guide member is effected in accordance with the height of successive stud members, said responsive means including a cam follower resiliently maintained against said stud members and a mechanical linkage connecting said cam follower and said guide member.

8. A grid winding machine of the type in which a grid wire is wound around a plurality of spaced support rods comprising means for rotating said side rods, means for longitudinally advancing said support rods simultaneously with said rotating movement, a guide member movable in a longitudinal direction with respect to the direction of advancement of said side rods for directing said grid wire onto said rotating support rods, means for effecting the movement of said guide member, said latter means comprising a rotatable cam having a plurality of stud members of varying heights, the height of each stud member being individually adjustable, a cam follower resiliently maintained against successive stud members, and means for rotating said cam to provide that each successive stud member comes under said cam follower simultaneously with the winding of one half grid turn and means operably connecting said cam follower and said guide member whereby said guide member is moved an amount corresponding to the height of successive stud members.

9. A grid winding machine of the lathe type in which a grid wire is wound around a pair of support rods comprising means for rotating said side rods, means for longitudinally advancing said support rods at a uniform rate, a guide member movable in a longitudinal direction with respect to the direction of advancement of said support rods for directing said grid wire onto said rotating support rods, means for effecting the movement of said guide member to provide that successive turns of said guide wire are unequally spaced, said movement eitecting means comprising a substantially disc-shaped member rotatable about its center and having a plurality of stud members extending perpendicularly from one flat surface thereof, said stud members being of varying height, the height of each stud member being individually adjustable, a cam follower resiliently maintained against said tud members successively one at a time, means for rotating said disc including a ratchet drive assembly operably responsive to the rate of rotation of said support rods to provide that said disc rotates an amount sufficient to bring each successive stud member under said cam follower during one half revolution of said support rods, means operably connecting said cam follower and said guide means whereby said guide means is moved in accordance with the difference in height of successive stud members to provide a difference in spacing between successive turns of said grid wire on said support rods, and means for the selective determination of the period during which said guide member is moved.

110. A method of winding a grid structure including a pair of spaced support rods having a grid wire wound thereabout in which the grid Wires are of variable pitch comprising the steps of rotating said support rods; longi tudinally moving said support rods at a uniform rate of speed; applying a grid wire to said support rods by means of a guide member; While said support rod is being longitudinally moved, directing said guide member in a longitudinal direction with respect to said support rods to provide that successive turns on said support rods are of different spacing.

11. A method of winding a grid structure including Cir a pair of spaced support rods having a grid wire wound thereabout to provide a plurality of grid turns comprising the steps of rotating said support rods, longitudinally advancing said support rods, applying said grid Wire to said support rods by means of a guide member, moving said guide member longitudinally with respect to said support rods during a predetermined portion of the longitudinal movement of said support rod whereby the grid turns wound during said predetermined portion are of a diiierent spacing than those wound at times other than that of said predetermined portion.

12. A grid winding machine of the lathe type in which a grid wire is wound around a pair of support rods comprising means for rotating said support rods, means for longitudinally advancing said support rods, guide means for directing said grid wire onto said rotating support rods, and means for varying the relative speed at which said support rods are longitudinally moved with respect to said guide means, said varying means comprising a substantially disc-shaped member rotatable about its center and having a plurality of cam surfaces extending perpendicularly from one flat surface thereof, said stud members being of varying height, the height of each stud member being individually adjustable, and a cam follower resiliently maintained against said cam surfaces successively one at a time, means for rotating said disc to successively bring individual cam surfaces under said cam follower to provide that the relative speed at which said support rods are moved with respect to said guide means is varied in accordance with the height of said cam surfaces.

References Cited by the Examiner UNITED STATES PATENTS 2,188,906 2/40 Lackey 140-715 2,778,386 1/57 Lindsay 140-715 2,820,487 1/58 Bahm 140-71.5 2,853,104 9/58 Johnson l4071.5 2,959,367 11/60 Kuba et al 140-715 CHARLES W. LANHAM, Primary Examiner.

WILLIAM F. PURDY, MICHAEL V. BRINDISI,

Examiners. 

1. A GRID WINDING MACHINE OF THE LATHE TYPE IN WHICH GRID WIRE IS WOUND ABOUT SPACED SUPPORT RODS COMPRISING MEANS FOR ROTATING SAID SUPPORT RODS, MEANS FOR ADVANCING SAID SUPPORT RODS IN THE DIRECTION OF THEIR ROTATIONAL AXIS AT A UNIFORM RATE, GUIDE MEANS FOR DIRECTING SAID GRID WIRE ONTO SAID ROTATING SUPPORT RODS, SAID GUIDE MEANS DISPLACEABLE IN A DIRECTION SUBSTANTIALLY PARALLEL TO THE DIRECTION OF ADVANCEMENT OF SAID SUPPORT RODS, AND MEANS RESPONSIVE TO THE MOTION OF SAID SUPPORT RODS FOR MOVING SAID GUIDE MEANS. 